Silicon compound containing epoxy group and thermosetting resin composition

ABSTRACT

The present invention relates to an epoxy group-containing silicon compound which is obtained by condensing at least one epoxy group-containing alkoxy silicon compound per se represented by the general formula (1a): R 1a Si(OR 2 ) 3 , wherein R 1a  denotes a substituent having an epoxy group and R 2  denotes an alkyl group having at most 4 carbons, or said compound and at least one substituted alkoxy silicon compound represented by the general formula (1b): R 1b Si(OR 3 ) 3 , wherein R 1b  denotes an alkyl group having at most 10 carbons, an aryl group or an unsaturated aliphatic residue and R 3  denotes an alkyl group having at most 4 carbons, in the presence of a basic catalyst.

TECHNICAL FIELD

The present invention relates to a novel epoxy group-containing siliconcompound and a thermosetting resin composition containing said novelepoxy group-containing silicon compound which provides a cured productexcellent in heat resistance which is used for various insulatingmaterials for electrical and electronic parts, various compositematerials such as laminated sheet (printed wiring board) and FRP(fiber-reinforced plastic), adhesives, paints, and the like.

BACKGROUND ART

An epoxy resin is excellent in heat resistance, electric properties,dynamic properties, and the like and therefore widely used in the fieldsof various electrical and electronic parts, structural materials,adhesives, paints, and the like. Furthermore, in accordance with recentdevelopment of electrical and electronic fields, request for an epoxyresin has been higher, and particularly improvement of heat resistancehas been required.

As a means for improving heat resistance of an epoxy resin, there are amethod of improving structure of the epoxy resin itself by increasingfunctional group density in the epoxy resin to increase cross-linkdensity of the cured product or by introducing a stiff skeleton into theresin skeleton, and a method of filling fillers such as glass fibers,silica particles, and mica. However, such a means by structureimprovement of the epoxy resin itself or addition of fillers or the likehas not attained sufficient improvement effects.

A heat resistance improvement method other than structure improvement ofthe epoxy resin itself or addition of fillers or the like is disclosedin, for example, JP-A 2001-59013 publication. Said publication proposesa method of using an alkoxy group-containing silane-modified epoxy resinwhich is obtained by subjecting a bisphenol A type epoxy resin and ahydrolyzable alkoxysilane to dealcoholization reaction. However, withregard to this method, there is pointed out a problem that defects suchas voids tend to be caused in the cured product due to the alcohol andwater produced as by-products.

Furthermore, as a compound having in the molecule silicon and an epoxygroup similarly to said alkoxy group-containing silane-modified epoxyresin, JP-A 10-324749 publication proposes a polyorganosiloxane havingan epoxy group and the preparation process thereof. However, thisprocess necessitates a step of end-capping a hydroxyl group and/or analkoxy group at the main chain terminals in order to improve stability.Moreover, in order to obtain the target product, the processnecessitates multiple steps of introducing a mercapto group in advanceand subjecting the group and an epoxy group-containing ethylenicallyunsaturated compound to Michel addition reaction in the presence of aradical initiator, and is not efficient. In addition, heat resistance ofthe resultant epoxy group-containing polyorganosiloxane is not referredto.

DISCLOSURE OF THE INVENTION

Therefore, one of the objects of the present invention is to provide athermosetting resin composition which gives the cured product excellentin heat resistance without depending on the conventional heat resistanceimprovement means.

Another object of the present invention is to provide a novel and stableepoxy group-containing silicon compound which can be one component ofsuch a composition.

Another further object of the present invention is to provide a processfor efficiently preparing such an epoxy group-containing siliconcompound.

In order to solve the above-mentioned problems in the prior art, thepresent inventors have devoted themselves to research and thus haveaccomplished the present invention. That is, the present inventionrelates to the following constitutions.

(1) An epoxy group-containing silicon compound which is obtained bycondensing at least one epoxy group-containing alkoxy silicon compoundper se represented by the general formula (1a): R_(1a)Si(OR₂)₃, whereinR_(1a) denotes a substituent having an epoxy group and R₂ denotes analkyl group having at most 4 carbons, in the presence of a basiccatalyst.

(2) An epoxy group-containing silicon compound which is obtained bycondensing at least one epoxy group-containing alkoxy silicon compoundrepresented by the general formula (1a): R_(1a)Si(OR₂)₃, wherein R_(1a)denotes a substituent having an epoxy group and R₂ denotes an alkylgroup having at most 4 carbons, and at least one substituted alkoxysilicon compound represented by the general formula (1b):R_(1b)Si(OR₃)₃, wherein R_(1b) denotes an alkyl group having at most 10carbons, an aryl group or an unsaturated aliphatic residue and R₃denotes an alkyl group having at most 4 carbons, in the presence of abasic catalyst.

(3) The epoxy group-containing silicon compound as set forth in theabove item (1) or (2), wherein R_(1a) is a glycidoxy(C1-C3)alkyl groupor an alkyl group substituted with a cycloalkyl group of 5-8 carbonshaving an oxirane group in each of said at least one epoxygroup-containing alkoxy silicon compound represented by the generalformula (1a).

(4) The epoxy group-containing silicon compound as set forth in theabove item (2), wherein R_(1b) is an alkyl group having at most 6carbons or an aryl group in each of said at least one substituted alkoxysilicon compound represented by the general formula (1b).

(5) The epoxy group-containing silicon compound as set forth in theabove item (2), wherein R_(1a) is a glycidoxy(C1-C3)alkyl group or analkyl group substituted with a cycloalkyl group of 5-8 carbons having anoxirane group in each of said at least one epoxy group-containing alkoxysilicon compound represented by the general formula (1a), and whereinR_(1b) is an alkyl group having at most 6 carbons or an aryl group ineach of said at least one substituted alkoxy silicon compoundrepresented by the general formula (1b).

(6) A thermosetting resin composition containing (i) the epoxygroup-containing silicon compound as set forth in any one of the aboveitems (1)-(5) and (ii) a curing agent.

(7) The thermosetting resin composition as set forth in the above item(6), which further contains an epoxy resin other than theabove-mentioned (i).

(8) The thermosetting resin composition as set forth in the above item(6) or (7), which further contains an accelerator and/or an organicsolvent.

(9) A cured product obtained by curing the thermosetting resincomposition as set forth in any one of the above items (6)-(8).

(10) A method for producing an epoxy group-containing silicon compound,which comprises condensing at least one epoxy group-containing alkoxysilicon compound per se represented by the general formula (1a):R_(1a)Si(OR₂)₃, wherein R_(1a) denotes a substituent having an epoxygroup and R₂ denotes an alkyl group having at most 4 carbons, in thepresence of a basic catalyst.

(11) A method for producing an epoxy group-containing silicon compound,which comprises condensing at least one epoxy group-containing alkoxysilicon compound represented by the general formula (1a):R_(1a)Si(OR₂)₃, wherein R_(1a) denotes a substituent having an epoxygroup and R₂ denotes an alkyl group having at most 4 carbons, and atleast one substituted alkoxy silicon compound represented by the generalformula (1b): R_(1b)Si(OR₃)₃, wherein R_(1b) denotes an alkyl grouphaving at most 10 carbons, an aryl group or an unsaturated aliphaticresidue and R₃ denotes an alkyl group having at most 4 carbons, in thepresence of a basic catalyst.

(12) The method as set forth in the above item (10) or (11), whereinR_(1a) is a glycidoxy(C1-C3)alkyl group or an alkyl group substitutedwith a cycloalkyl group of 5-8 carbons having an oxirane group in eachof said at least one epoxy group-containing alkoxy silicon compoundrepresented by the general formula (1a).

(13) The method as set forth in the above item (11), wherein R_(1b) isan alkyl group having at most 6 carbons or an aryl group in each of saidat least one substituted alkoxy silicon compound represented by thegeneral formula (1b).

(14) The method as set forth in the above item (11), wherein R_(1a) is aglycidoxy(C1-C3)alkyl group or an alkyl group substituted with acycloalkyl group of 5-8 carbons having an oxirane group in each of saidat least one epoxy group-containing alkoxy silicon compound representedby the general formula (1a), and wherein R_(1b) is an alkyl group havingat most 6 carbons or an aryl group in each of said at least onesubstituted alkoxy silicon compound represented by the general formula(1b).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows evaluation results of heat resistance of the cured productsobtained in Examples 2 and 4 and Comparative Example 1. The ordinateaxis and transverse axis therein indicate dynamic storage elasticmodulus and temperature, respectively.

FIG. 2 shows evaluation results of heat resistance of the cured productsobtained in Examples 6 and 8 and Comparative Example 1. The ordinateaxis and transverse axis therein indicate dynamic storage elasticmodulus and temperature, respectively.

FIG. 3 shows evaluation results of heat resistance of the cured productsobtained in Examples 10 and 12 and Comparative Example 1. The ordinateaxis and transverse axis therein indicate dynamic storage elasticmodulus and temperature, respectively.

FIG. 4 shows evaluation results of heat resistance of the cured productsobtained in Examples 14 and 16 and Comparative Example 1. The ordinateaxis and transverse axis therein indicate dynamic storage elasticmodulus and temperature, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention isdescribed, and “part” and “%” are based on weight, unless otherwisenoted.

As mentioned above, the epoxy group-containing silicon compound of thepresent invention is obtained by condensing at least one epoxygroup-containing alkoxy silicon compound per se represented by thegeneral formula (1a): R_(1a)Si(OR₂)₃, wherein R_(1a) denotes asubstituent having an epoxy group and R₂ denotes an alkyl group havingat most 4 carbons, in the presence of a basic catalyst, or by condensingat least one epoxy group-containing alkoxy silicon compound representedby the general formula (1a): R_(1a)Si(OR₂)₃, wherein R_(1a) denotes asubstituent having an epoxy group and R₂ denotes an alkyl group havingat most 4 carbons, and at least one substituted alkoxy silicon compoundrepresented by the general formula (1b): R_(1b)Si(OR₃)₃, wherein R_(1b)denotes an alkyl group having at most 10 carbons, an aryl group or anunsaturated aliphatic residue and R₃ denotes an alkyl group having atmost 4 carbons, in the presence of a basic catalyst. Herein, “at leastone epoxy group-containing alkoxy silicon compound represented by thegeneral formula (1a) . . . ” and “at least one substituted alkoxysilicon compound represented by the general formula (1b) . . . ” meanthat only one kind of the compounds represented by these formulas may beused or a mixture of two or more kinds may be used. In addition, “perse” concerning condensation of the compound represented by the generalformula (1a) means that without combining with the compound of thegeneral formula (1b), condensation is carried out between the samemolecules of a kind of compound of the general formula (1a) or betweendifferent molecules of two or more kinds of compounds of the generalformula (1a).

As the epoxy group-containing substituent, R_(1a) in the epoxygroup-containing alkoxy silicon compound of the formula (1a) used in thepresent invention, there is no particular limitation so long as it is asubstituent having an epoxy group, and there are cited glycidoxyalkylgroups of at most 4 carbons having oxyglycidyl group such asβ-glycidoxyethyl, γ-glycidoxypropyl, and γ-glycidoxybutyl; glycidyl;alkyl groups substituted with cycloalkyl group of 5-8 carbons havingoxirane group such as β-(3,4-epoxycyclohexyl)ethyl,γ-(3,4-epoxycyclohexyl)propyl, β-(3,4-epoxycycloheptyl)ethyl,β-(3,4-epoxycyclohexyl)propyl, β-(3,4-epoxycyclohexyl)butyl, andβ-(3,4-epoxycyclohexyl)pentyl; and the like. Above all, preferable areglycidoxyalkyl groups wherein oxyglycidyl group is bonded to alkyl groupof 1-3 carbons, and alkyl groups of at most 3 carbons substituted withcycloalkyl group of 5-8 carbons having oxirane group, for example,β-glycidoxyethyl, y-glycidoxypropyl, β-(3,4-epoxycyclohexyl)ethyl, andthe like.

Furthermore, as examples of R₂ in the epoxy group-containing alkoxysilicon compound of the formula (1a), there are cited alkyl groups of atmost 4 carbons such as methyl, ethyl, n-propyl, i-propyl, n-butyl,i-butyl, and tert-butyl. Most preferably R₂ is methyl or ethyl from theviewpoint of reaction conditions such as compatibility, reactivity, andreaction yield.

As preferable specific examples of the compound of the formula (1a)having these substituents R_(1a) and R₂ which can be used, there arecited

β-glycidoxyethyltrimethoxysilane,

β-glycidoxyethyltriethoxysilane,

γ-glycidoxypropyltrimethoxysilane,

γ-glycidoxypropyltriethoxysilane,

β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,

β-(3,4-epoxycyclohexyl)ethyltriethoxysilane,

and the like.

As examples of R_(1b) in the substituted alkoxy silicon compound of theformula (1b) used in the present invention, there are cited an alkylgroup having at most 10 carbons such as methyl, ethyl, propyl, butyl,pentyl, hexyl, heptyl, octyl, nonyl, or decanyl; an aryl group; and anunsaturated aliphatic residue such as methacryloyl group or acryloylgroup. Preferably R_(1b) is an alkyl group having at most 6 carbons oran aryl group.

Furthermore, as examples of R₃ in the substituted alkoxy siliconcompound of the formula (1b), there are cited alkyl groups having atmost 4 carbons such as methyl, ethyl, n-propyl, i-propyl, n-butyl,i-butyl, and tert-butyl. Most preferably R₃ is methyl or ethyl from theviewpoint of reaction conditions such as compatibility, reactivity, andreaction yield.

As preferable specific examples of the compound of the formula (1b)having these substituents R_(1b) and R₃ which can be used, there arecited alkyltrialkoxysilanes such as methyltrimethoxysilane,methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane,ethyltrimethoxysilane, ethyltriethoxysilane, iobutyltrimethoxysilane,iobutyltriethoxysilane, n-propyltrimethoxysilane,n-propyltriethoxysilane, isopropyltrimethoxysilane,isopropyltriethoxysilane, decyltrimethoxysilane, anddecyltriethoxysilane; and aryltrialkoxysilanes such asphenyltrimethoxysilane and phenyltriethoxysilane; and the like.

When among compounds of the formula (1b), compounds having thepreferable substituents as mentioned above as R_(1b) (or a combinationof R_(1b) and R₃) are used, improvements are found in the points ofcompatibility with other components in the thermosetting composition ofthe present invention to be hereinafter described and physicalproperties of the cured product of the composition.

When the epoxy group-containing alkoxy silicon compound of the formula(1a) and the substituted alkoxy silicon compound of the formula (1b) areused together in order to obtain the epoxy group-containing siliconcompound of the present invention, it is possible to appropriatelydetermine the proportion of the compound of the formula (1b) used inaccordance with the desired physical properties of the cured product.That is, it is possible to use the compound of the formula (1b) in aproportion of usually not more than 95 mole %, preferably not more than90 mole % based on the total moles of the compound of the formula (1a)and the compound of the formula (1b). When the proportion of thecompound of the formula (1b) used is larger, heat resistance of thecured product tends to decrease. Therefore, when the cured producthaving high heat resistance is desired, the compound of the formula (1b)is used in a proportion of not more than 75 mole %, preferably about70-5 mole % based on the total moles of the compound of the formula (1a)and the compound of the formula (1b). However on the other hand, whenthe proportion of the compound of the formula (1b) used is larger, thereis the advantage that improvement is found in tackiness (stickinessdegree) of the cured product. Furthermore, in this case, refractiveindex is higher, and it is possible to design cured products differentin refractive index to desired extent, and hence they can be used for,for example, optical waveguide and the like.

The epoxy group-containing silicon compound of the present invention canbe obtained by the condensation reaction in which the epoxygroup-containing alkoxy silicon compound of the formula (1a) is used asan essential component, that is, can be obtained by condensing thecompound (one kind or plural kinds) of the formula (1a) per se, or asnecessary, the compound (one kind or plural kinds) of the formula (1a)and the substituted alkoxy silicon compound (one kind or plural kinds)of the formula (1b) in the presence of a basic catalyst. Furthermore, inorder to accelerate condensation, water can be added as necessary. Theamount of water added is usually 0.05-1.5 moles, preferably 0.07-1.2moles based on 1 mole of alkoxy group of the entire reaction mixture. Inaddition, more preferably in the present invention, the compound (onekind or plural kinds) of the formula (1a) per se is condensed.

The catalyst used in the above-mentioned condensation reaction is notparticularly limited, so long as it is basic, and it is possible to usean inorganic base such as an alkali metal hydroxide such as sodiumhydroxide, potassium hydroxide, lithium hydroxide, or cesium hydroxide;an alkali metal carbonate such as sodium carbonate, potassium carbonate,sodium hydrogen carbonate, or potassium hydrogen carbonate; or the like;or an organic base such as ammonia, triethylamine, diethylenetriamine,n-butylamine, dimethylaminoethanol, triethanolamine, tetramethylammoniumhydroxide, or the like. Among them, an inorganic base or ammonia ispreferable particularly in the point that catalyst removal from theproduct is easy. The amount of catalyst added can be usually5×10⁻⁴-7.5%, preferably 1×10⁻³-5% based on the total weight of the epoxygroup-containing alkoxy silicon compound of the formula (1a) and thesubstituted alkoxy silicon compound of the formula (1b). When an alkalimetal hydroxide or an alkali metal carbonate is used as a catalyst, theamount is preferably about 0.01-0.1%.

The above-mentioned condensation reaction can be carried out in asolvent or in no solvent. The solvent is not particularly limited, solong as it dissolves the epoxy group-containing alkoxy silicon compoundof the formula (1a) and the substituted alkoxy silicon compound of theformula (1b). As such a solvent, there can be enumerated, for example,an aprotic polar solvent such as dimethylformamide, dimethylacetamide,tetrahydofuran, methyl ethyl ketone, or methyl isobutyl ketone; anaromatic hydrocarbon such as toluene or xylene; or the like. Among them,an aprotic polar solvent is preferable. The amount of a solvent used isnot particularly limited so long as it is in the range where thereaction proceeds smoothly, but too much amount necessitates long timeto be removed and makes working efficiency bad, and therefore it is usedusually in about 80-150 parts based on 100 parts of the total weight ofthe compounds of the formula (1a) and the formula (1b).

The reaction is carried out by mixing the compound of the formula (1a)and if necessary the compound of the formula (1b) and a solvent, andheating the mixture to 40-140° C., and then adding a basic catalyst. Inaddition, the total amount of the basic catalyst may be added beforeheating. Furthermore, the basic catalyst can be added as a solid or anaqueous solution of about 0.05-0.3%, but preferably the aqueous solutionis gradually dropped in order to prevent excess proceeding of thereaction. After completion of the dropping, the reaction is continuedfor 1-12 hours at 40-140° C., while removing alcohols produced by thereaction. In addition, it is possible to continue the reaction withoutremoving the alcohols. After completion of the reaction, the product iswashed until the used wash becomes neutral. In addition, when a solventis used, the solvent is removed after washing under reduced pressure.

The weight average molecular weight of the epoxy group-containingsilicon compound of the present invention thus obtained is preferably400-50,000, more preferably 750-30,000, further preferably 1,200-10,000,particularly preferably about 2,000-7,000. When the weight averagemolecular weight is less than 400, improvement effect in heat resistanceis lean. On the other hand, when it is larger than 50,000, deteriorationof physical properties as the corresponding thermosetting compositionsuch as descent of compatibility with other components and ascent ofviscosity is caused, which is not preferable.

The epoxy group-containing silicon compound of the present invention isprovided for various uses, and usually used as a thermosetting resincomposition in combination with a curing agent. Furthermore, in applyingthe present silicon compound to various uses, it can be used togetherwith various epoxy resins other than the epoxy group-containing siliconcompound of the present invention in accordance with uses.

As a curing agent, usually, there can be used without particularlimitation amine type compounds, amide type compounds, acid anhydridetype compounds, phenol type compounds, imidazoles, Lewis acids, and thelike which have been used as a curing agent for an epoxy resin.Specifically, there are cited amine type compounds such asdiaminodiphenylmethane, diethylenetriamine, triethylenetetramine,diaminodiphenylsulfone, isophorone diamine, dimethylbenzylamine,tetraethylenepentamine, ketimine compounds, and guanidine derivatives;amide type compounds such as dicyandiamide, and polyamide resinsynthesized from dimmer of linolenic acid and ethylene diamine; acidanhydride type compounds such as phthalic anhydride, trimelliticanhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalicanhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride,hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride;phenol type compounds such as bisphenols, polycondensates of phenols(phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol,dihydroxybenzene, dihydroxynaphthalene, and the like) and variousaldehydes, polymerization products of phenols and various dienecompounds, polycondensates of phenols and aromatic dimethylols,condensates of bismethoxymethylbiphenyl and naphthols or phenols,biphenols and the modification products thereof; imidazoles such asimidazole; Lewis acids such as boron trifluoride-amine complex; and thelike. The amount of a curing agent used is preferably 0.2-1.5equivalents, particularly preferably 0.3-1.2 equivalents based on 1equivalent of epoxy group in the composition. Furthermore, a tertiaryamine such as benzyldimethylamine can be used as a curing agent, and theamount in using it is usually 0.3-20%, preferably 0.5-10% based on anepoxy group-containing compound.

The thermosetting resin composition of the present invention can containan accelerator if necessary. As an accelerator there are cited, forexample, imidazoles such as 2-methylimidazole, 2-ethylimidazole, and2-ethyl-4-methylimidazole; tertiary amines such as2-(dimethylaminomethyl)phenol, and 1,8-diaza-bicyclo(5,4,0)undecene-7;phosphines such as triphenylphosphine; metal compounds such as tinoctanoate; quaternary phosphonium salts; and the like. An accelerator isused as necessary in an amount of 0.01-15 parts based on 100 parts of anepoxy group-containing compound in the composition.

When the epoxy group-containing silicon compound of the presentinvention is used together with the other epoxy resins in thethermosetting resin composition of the present invention, the proportionof the epoxy group-containing silicon compound of the present inventionin all epoxy group-containing compounds is preferably at least 10%. Theother epoxy resins which can be used, are not particularly limited, solong as they are epoxy resins which are usually used for electrical andelectronic parts, and can be obtained usually by glycidylating acompound having two or more phenolic hydroxyl groups. As specificexamples of usable epoxy resins, there are cited glycidylation productsof bisphenols such as tetrabromobisphenol A, tetrabromobisphenol F,bisphenol A, tetramethylbisphenol F, bisphenol F, bisphenol S, andbisphenol K; or biphenols such as biphenol and tetramethylbiphenol; orhydroquinones such as hydroquinone, methylhydroquinone,dimethylhydroquinone, trimethylhydroquinone, di-tertiarybutylhydroquinone; or resorcinols such as resorcinol, andmethylresorcinol; or catechols such as catechol, and methylcatechol; ordihydroxynaphthalenes such as dihydroxynaphthalene,dihydroxymethylnaphthalene, and dihydroxydimethylnaphthalene; andglycidylation products of condensates between phenols or naphthols andaldehydes, or condensates between phenols or naphthols and xylyleneglycol, or condensates between phenols and isopropenylacetophenone, orreaction products between phenols and dicyclopentadiene, or condensatesbetween bismethoxymethylbiphenyl and naphthols or phenols; and the like.These are commercially available or can be obtained by known methods.These may be used alone or in a combination of two or more kinds.

Furthermore, to the thermosetting resin composition of the presentinvention there can be added various formulating ingredients such asfiller of silica, alumina, glass fiber, talc or the like; mold releasingagent, pigment, surface treatment, viscosity modifier, plasticizer,stabilizer, and coupling agent as necessary.

Moreover, the thermosetting resin composition of the present inventioncan be used as a varnish by containing an organic solvent. As an organicsolvent, there is no particular limitation so long as it dissolves eachcomponent of the composition, and there are cited, for example, toluene,xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone,dimethylformamide, and the like. The cured product of the presentinvention may be obtained by impregnating the varnish dissolved in suchan organic solvent into a base material such as glass fibers, carbonfibers, polyester fibers, polyamide fibers, alumina fibers, or paper,drying under heating to get a prepreg, and molding the prepreg byhot-pressing.

An organic solvent can be used in such an amount that the proportion ofthe organic solvent in the thermosetting resin composition can beusually 10-70%, preferably 15-65%.

The thermosetting resin composition of the present invention can beobtained by mixing each component uniformly. The thermosetting resincomposition of the present invention can be easily changed into itscured product by a method similar to those which have been heretoforeknown. For example, an epoxy group-containing compound and a curingagent, and optionally an accelerator and other formulating ingredientsas necessary are sufficiently blended until they become uniform by useof an extruder, a kneader, a roll or the like to obtain an epoxy resincomposition. Thereafter, the epoxy resin composition can be molten andthen casted or molded by use of a transfer molding machine, andfurthermore can be heated for 2-10 hours at 80-200° C. to obtain thecured product.

EXAMPLES 1-13 AND COMPARATIVE EXAMPLE 1

The present invention is specifically described by way of workingexamples, but the present invention is not limited by them.

Physical property values in the working examples were measured by thefollowing methods.

(1) Weight average molecular weight: was measured by GPC (gel permeationchromatography) method.

(2) Epoxy equivalent: was measured by a method pursuant to JIS K-7236.

EXAMPLE 1

94.4 parts of γ-glycidoxypropyltrimethoxysilane and 94.4 parts of methylisobutyl ketone were charged in a reaction vessel and heated to 80° C.After heating, 21.6 parts of 0.1% potassium hydroxide aqueous solutionwas continuously dropped in 30 minutes. After completion of dropping,reaction was continued for 5 hours at 80° C. while removing theresulting methanol. After completion of the reaction, washing wasrepeated until the used wash becomes neutral. Then the solvent wasremoved under reduced pressure to obtain 67 parts of the epoxygroup-containing silicon compound (A) of the present invention. Theepoxy equivalent of the resultant compound was 166 g/eq., and the weightaverage molecular weight thereof was 3700. From ¹H-NMR (CDCl₃ solution)of the present epoxy compound (A), it could be confirmed that epoxy ringis retained due to the methine peak (in the vicinity of 3.2 ppm) ofepoxy ring and that the peak (in the vicinity of 3.6 ppm) of methoxygroup has disappeared. Furthermore, gelation was not observed even afterelapse of one month at room temperature.

EXAMPLE 2

7.5 parts of the epoxy group-containing silicon compound (A) obtained inExample 1, 7.5 parts of bisphenol A type epoxy resin (epoxy equivalent:186 g/eq., Epikote 828 manufactured by Japan Epoxy Resin K.K.), and 4.1parts of diaminodiphenylmethane were uniformly mixed to prepare thethermosetting resin composition of the present invention. Thecomposition prepared was poured into an aluminium cup and heated at 60°C., 100° C., 150° C., and 190° C. successively for each 4 hours toobtain a cured product. Defects such as voids were not found in theresultant cured product.

EXAMPLE 3

100 parts of β-(3,4epoxycyclohexyl)ethyltrimethoxysilane and 100 partsof methyl isobutyl ketone were charged in a reaction vessel and heatedto 80° C. After heating, 21.6 parts of 0.1% potassium hydroxide aqueoussolution was continuously dropped in 30 minutes. After completion ofdropping, reaction was continued for 5 hours at 80° C. while removingthe resulting methanol. After completion of the reaction, washing wasrepeated until the used wash becomes neutral. Then the solvent wasremoved under reduced pressure to obtain 72 parts of the epoxygroup-containing silicon compound (B) of the present invention. Theepoxy equivalent of the resultant compound was 179 g/eq., and the weightaverage molecular weight thereof was 5600. From ¹H-NMR (CDCl₃ solution)of the present epoxy compound (B), it could be confirmed that epoxy ringis retained due to the methine peak (in the vicinity of 3.2 ppm) ofepoxy ring and that the peak (in the vicinity of 3.6 ppm) of methoxygroup has disappeared. Furthermore, gelation was not observed even afterelapse of one month at room temperature.

EXAMPLE 4

7.5 parts of the epoxy group-containing silicon compound (B) obtained inExample 3, 7.5 parts of bisphenol A type epoxy resin (epoxy equivalent:186 g/eq., Epikote 828 manufactured by Japan Epoxy Resin K.K.), and 4.0parts of diaminodiphenylmethane were uniformly mixed to prepare thethermosetting resin composition of the present invention. Thecomposition prepared was cured in the similar way to Example 2 to obtaina cured product. Defects such as voids were not found in the resultantcured product.

EXAMPLE 5

67 parts of the epoxy group-containing silicon compound (C) of thepresent invention was obtained similarly to Example 1 except that 21.6parts of 0.1% potassium hydroxide aqueous solution was changed to 10.8parts of 0.1% sodium hydroxide aqueous solution in Example 1. The epoxyequivalent of the resultant compound was 169 g/eq., and the weightaverage molecular weight thereof was 3100. From ¹H-NMR (CDCl₃ solution)of the present epoxy compound (C), it could be confirmed that epoxy ringis retained due to the methine peak (in the vicinity of 3.2 ppm) ofepoxy ring and that the peak (in the vicinity of 3.6 ppm) of methoxygroup has disappeared. Furthermore, gelation was not observed even afterelapse of one month at room temperature.

EXAMPLE 6

10.0 parts of the epoxy group-containing silicon compound (C) obtainedin Example 5, 5.5 parts of bisphenol A type epoxy resin (epoxyequivalent: 186 g/eq., Epikote 828 manufactured by Japan Epoxy ResinK.K.), and 4.4 parts of diaminodiphenylmethane were uniformly mixed toprepare the thermosetting resin composition of the present invention.The composition prepared was cured in the similar way to Example 2 toobtain a cured product. Defects such as voids were not found in theresultant cured product.

EXAMPLE 7

85 parts of γ-glycidoxypropyltrimethoxysilane, 7.9 parts ofphenyltrimethoxysilane, and 92.9 parts of methyl isobutyl ketone werecharged in a reaction vessel and heated to 80° C. After heating, 10.8parts of 0.1% potassium hydroxide aqueous solution was continuouslydropped in 30 minutes. After completion of dropping, reaction wascontinued for 5 hours at 80° C. while removing the resulting methanol.After completion of the reaction, washing was repeated until the usedwash becomes neutral. Then the solvent was removed under reducedpressure to obtain 65 parts of the epoxy group-containing siliconcompound (D) of the present invention. The epoxy equivalent of theresultant compound was 184 g/eq., and the weight average molecularweight thereof was 2900. From ¹H-NMR (CDCl₃ solution) of the presentepoxy compound (D), it could be confirmed that epoxy ring is retaineddue to the methine peak (in the vicinity of 3.2 ppm) of epoxy ring andthat the peak (in the vicinity of 3.6 ppm) of methoxy group hasdisappeared. Furthermore, gelation was not observed even after elapse ofone month at room temperature.

EXAMPLE 8

10.0 parts of the epoxy group-containing silicon compound (D) obtainedin Example 7, 5.5 parts of bisphenol A type epoxy resin (epoxyequivalent: 186 g/eq., Epikote 828 manufactured by Japan Epoxy ResinK.K.), and 4.2 parts of diaminodiphenylmethane were uniformly mixed toprepare the thermosetting resin composition of the present invention.The composition prepared was cured in the similar way to Example 2 toobtain a cured product. Defects such as voids were not found in theresultant cured product.

EXAMPLE 9

66 parts of the epoxy group-containing silicon compound (E) of thepresent invention was obtained similarly to Example 1 except that 21.6parts of 0.1% potassium hydroxide aqueous solution was changed to 11.5parts of 0.5% potassium carbonate aqueous solution in Example 1. Theepoxy equivalent of the resultant compound was 173 g/eq., and the weightaverage molecular weight thereof was 3200. From ¹H-NMR (CDCl₃ solution)of the present epoxy compound (E), it could be confirmed that epoxy ringis retained due to the methine peak (in the vicinity of 3.2 ppm) ofepoxy ring and that the peak (in the vicinity of 3.6 ppm) of methoxygroup has disappeared. Furthermore, gelation was not observed even afterelapse of one month at room temperature.

EXAMPLE 10

10.5 parts of the epoxy group-containing silicon compound (E) obtainedin Example 9, 6.0 parts of bisphenol A type epoxy resin (epoxyequivalent: 186 g/eq., Epikote 828 manufactured by Japan Epoxy ResinK.K.), and 4.6 parts of diaminodiphenylmethane were uniformly mixed toprepare the thermosetting resin composition of the present invention.The composition prepared was cured in the similar way to Example 2 toobtain a cured product. Defects such as voids were not found in theresultant cured product.

EXAMPLE 11

67 parts of the epoxy group-containing silicon compound (F) of thepresent invention was obtained similarly to Example 1 except that 21.6parts of 0.1% potassium hydroxide aqueous solution was changed to 11.5parts of 0.5% sodium carbonate aqueous solution in Example 1. The epoxyequivalent of the resultant compound was 168 g/eq., and the weightaverage molecular weight thereof was 3400. From ¹H-NMR (CDCl₃ solution)of the present epoxy compound (F), it could be confirmed that epoxy ringis retained due to the methine peak (in the vicinity of 3.2 ppm) ofepoxy ring and that the peak (in the vicinity of 3.6 ppm) of methoxygroup has disappeared. Furthermore, gelation was not observed even afterelapse of one month at room temperature.

EXAMPLE 12

10.6 parts of the epoxy group-containing silicon compound (F) obtainedin Example 11, 6.0 parts of bisphenol A type epoxy resin (epoxyequivalent: 186 g/eq., Epikote 828 manufactured by Japan Epoxy ResinK.K.), and 4.7 parts of diaminodiphenylmethane were uniformly mixed toprepare the thermosetting resin composition of the present invention.The composition prepared was cured in the similar way to Example 2 toobtain a cured product. Defects such as voids were not found in theresultant cured product.

EXAMPLE 13

33.1 parts of γ-glycidoxypropyltrimethoxysilane, 55.5 parts ofphenyltrimethoxysilane, and 88.6 parts of methyl isobutyl ketone werecharged in a reaction vessel and heated to 80° C. After heating, 11.4parts of 0.1% potassium hydroxide aqueous solution was continuouslydropped in 30 minutes. After completion of dropping, reaction wascontinued for 5 hours at 80° C. After completion of the reaction,washing was repeated until the used wash becomes neutral. Then thesolvent was removed under reduced pressure to obtain 60.3 parts of theepoxy group-containing silicon compound (G) of the present invention.The epoxy equivalent of the resultant compound was 436 g/eq., and theweight average molecular weight thereof was 3400. From ¹H-NMR (CDCl₃solution) of the present epoxy compound (G), it could be confirmed thatepoxy ring is retained due to the methine peak (in the vicinity of 3.2ppm) of epoxy ring and that the peak (in the vicinity of 3.6 ppm) ofmethoxy group has disappeared. Furthermore, gelation was not observedeven after elapse of one month at room temperature.

EXAMPLE 14

10 parts of the epoxy group-containing silicon compound (G) obtained inExample 13, 2.5 parts of bisphenol A type epoxy resin (epoxy equivalent:186 g/eq., Epikote 828 manufactured by Japan Epoxy Resin K.K.), and 3.6parts of diaminodiphenylmethane were uniformly mixed to prepare thethermosetting resin composition of the present invention. Thecomposition prepared was cured in the similar way to Example 2 to obtaina cured product. Defects such as voids were not found in the resultantcured product.

EXAMPLE 15

41.4 parts of γ-glycidoxypropyltrimethoxysilane, 67.8 parts ofβ-(3,4epoxycyclohexyl)ethyltrimethoxysilane, and 54.6 parts of methylisobutyl ketone were charged in a reaction vessel and heated to 80° C.After heating, 14.2 parts of 0.1% potassium hydroxide aqueous solutionwas continuously dropped in 30 minutes. After completion of dropping,reaction was continued for 5 hours at 80° C. After completion of thereaction, washing was repeated until the used wash becomes neutral. Thenthe solvent was removed under reduced pressure to obtain 78.2 parts ofthe epoxy group-containing silicon compound (H) of the presentinvention. The epoxy equivalent of the resultant compound was 177 g/eq.,and the weight average molecular weight thereof was 4200. From ¹H-NMR(CDCl₃ solution) of the present epoxy compound (H), it could beconfirmed that epoxy ring is retained due to the methine peak (in thevicinity of 3.2 ppm) of epoxy ring and that the peak (in the vicinity of3.6 ppm) of methoxy group has disappeared. Furthermore, gelation was notobserved even after elapse of one month at room temperature.

EXAMPLE 16

10 parts of the epoxy group-containing silicon compound (H) obtained inExample 15, 5.7 parts of bisphenol A type epoxy resin (epoxy equivalent:186 g/eq., Epikote 828 manufactured by Japan Epoxy Resin K.K.), and 4.3parts of diaminodiphenylmethane were uniformly mixed to prepare thethermosetting resin composition of the present invention. Thecomposition prepared was cured in the similar way to Example 2 to obtaina cured product. Defects such as voids were not found in the resultantcured product.

EXAMPLE 17

25 parts of γ-glycidoxypropyltrimethoxysilane, 75 parts ofphenyltrimethoxysilane, and 100 parts of methyl isobutyl ketone werecharged in a reaction vessel and heated to 80° C. After heating, 13.1parts of 0.1% potassium hydroxide aqueous solution was continuouslydropped in 30 minutes. After completion of dropping, reaction wascontinued for 5 hours at 80° C. while removing the resulting methanol.After completion of the reaction, washing was repeated until the usedwash becomes neutral. Then the solvent was removed under reducedpressure to obtain 69 parts of the epoxy group-containing siliconcompound (I) of the present invention. The epoxy equivalent of theresultant compound was 626 g/eq., and the weight average molecularweight thereof was 2400. From ¹H-NMR (CDCl₃ solution) of the presentepoxy compound (I), it could be confirmed that epoxy ring is retaineddue to the methine peak (in the vicinity of 3.2 ppm) of epoxy ring andthat the peak (in the vicinity of 3.6 ppm) of methoxy group hasdisappeared. Furthermore, gelation was not observed even after elapse ofone month at room temperature.

COMPARATIVE EXAMPLE 1

15 parts of bisphenol A type epoxy resin (epoxy equivalent: 186 g/eq.,Epikote 828 manufactured by Japan Epoxy Resin K.K.), and 4.0 parts ofdiaminodiphenylmethane were uniformly mixed to prepare a thermosettingresin composition. The composition prepared was cured in the similar wayto Example 2 to obtain a cured product.

[Heat Resistance Evaluation]

The cured products obtained in Examples 2, 4, 6, 8, 10, 12, 14, 16 andComparative Example 1 were shaped in a size of 4 mm width, 3 mmthickness, and 40 mm length, and dynamic storage elastic modulus wasmeasured by use of a dynamic viscoelasticity measuring apparatus (DMA2980 manufactured by TA Instruments Corporation, measurement conditions:amplitude 15 μm, frequency 10 Hz, and rate of temperature rise 2°C./min.) to evaluate heat resistance. Measurement results are shown inFIG. 1-4.

From FIG. 1-4, in Comparative Example 1 large decrease in elasticmodulus is found in accordance with rising of temperature. On the otherhand, in Examples 2, 4, 6, 8, 10, 12, 14, and 16 it is found thatdecrease of elastic modulus is low, elastic modulus at high temperatureis high, and heat resistance is excellent. That is, as temperaturepasses 150° C., in the cured product of the Comparative Example elasticmodulus decreases rapidly but in the cured products of the Examples theinitial values are almost retained. This fact means that the curedproduct of the present invention exhibits no glass transition point andis excellent in heat resistance.

INDUSTRIAL USABILITY

By using the thermosetting resin composition containing the epoxygroup-containing silicon compound of the present invention, remarkableimprovement is found in elastic modulus at high temperature, and thecured product excellent in heat resistance can be obtained. Thethermosetting resin composition of the present invention can be used asvarious insulating materials for electrical and electronic parts,printed wiring boards, laminated sheets such as high functionallycopper-clad laminate, semiconductor encapsulating materials, variouscomposite materials such as FRP (fiber-reinforced plastic), paints,adhesives, and coating agents. It provides the cured product excellentparticularly in heat resistance, and hence has recently been extremelyuseful as a thermosetting resin composition which can apply to thelead-free solder in use.

1. An epoxy group-containing silicon compound which is obtained bycondensing at least one epoxy group-containing alkoxy silicon compoundper se represented by the general formula (1a): R_(1a)Si(OR₂)₃, whereinR_(1a) denotes a substituent having an epoxy group and R₂ denotes analkyl group having at most 4 carbons, in the presence of a basiccatalyst.
 2. An epoxy group-containing silicon compound which isobtained by condensing at least one epoxy group-containing alkoxysilicon compound represented by the general formula (1a):R_(1a)Si(OR₂)₃, wherein R_(1a) denotes a substituent having an epoxygroup and R₂ denotes an alkyl group having at most 4 carbons, and atleast one substituted alkoxy silicon compound represented by the generalformula (1b): R_(1b)Si(OR₃)₃, wherein R_(1b) denotes an alkyl grouphaving at most 10 carbons, an aryl group or an unsaturated aliphaticresidue and R₃ denotes an alkyl group having at most 4 carbons, in thepresence of a basic catalyst.
 3. The epoxy group-containing siliconcompound as set forth in claim 1 or 2, wherein R_(1a) is aglycidoxy(C1-C3)alkyl group or an alkyl group substituted with acycloalkyl group of 5-8 carbons having an oxirane group in each of saidat least one epoxy group-containing alkoxy silicon compound representedby the general formula (1a).
 4. The epoxy group-containing siliconcompound as set forth in claim 2, wherein R_(1b) is an alkyl grouphaving at most 6 carbons or an aryl group in each of said at least onesubstituted alkoxy silicon compound represented by the general formula(1b).
 5. The epoxy group-containing silicon compound as set forth inclaim 2, wherein R_(1a) is a glycidoxy(C1-C3)alkyl group or an alkylgroup substituted with a cycloalkyl group of 5-8 carbons having anoxirane group in each of said at least one epoxy group-containing alkoxysilicon compound represented by the general formula (1a), and whereinR_(1b) is an alkyl group having at most 6 carbons or an aryl group ineach of said at least one substituted alkoxy silicon compoundrepresented by the general formula (1b).
 6. A thermosetting resincomposition containing (i) the epoxy group-containing silicon compoundas set forth in any one of claims 1-5 and (ii) a curing agent.
 7. Thethermosetting resin composition as set forth in claim 6, which furthercontains an epoxy resin other than the above-mentioned (i).
 8. Thethermosetting resin composition as set forth in claim 6 or 7, whichfurther contains an accelerator and/or an organic solvent.
 9. A curedproduct obtained by curing the thermosetting resin composition as setforth in any one of claims 6-8.
 10. A method for producing an epoxygroup-containing silicon compound, which comprises condensing at leastone epoxy group-containing alkoxy silicon compound per se represented bythe general formula (1a): R_(1a)Si(OR₂)₃, wherein R_(1a) denotes asubstituent having an epoxy group and R₂ denotes an alkyl group havingat most 4 carbons, in the presence of a basic catalyst.
 11. A method forproducing an epoxy group-containing silicon compound, which comprisescondensing at least one epoxy group-containing alkoxy silicon compoundrepresented by the general formula (1a): R_(1a)Si(OR₂)₃, wherein R_(1a)denotes a substituent having an epoxy group and R₂ denotes an alkylgroup having at most 4 carbons, and at least one substituted alkoxysilicon compound represented by the general formula (1b):R_(1b)Si(OR₃)₃, wherein R_(1b) denotes an alkyl group having at most 10carbons, an aryl group or an unsaturated aliphatic residue and R₃denotes an alkyl group having at most 4 carbons, in the presence of abasic catalyst.
 12. The method as set forth in claim 10 or 11, whereinR_(1a) is a glycidoxy(C1-C3)alkyl group or an alkyl group substitutedwith a cycloalkyl group of 5-8 carbons having an oxirane group in eachof said at least one epoxy group-containing alkoxy silicon compoundrepresented by the general formula (1a).
 13. The method as set forth inclaim 11, wherein R_(1b) is an alkyl group having at most 6 carbons oran aryl group in each of said at least one substituted alkoxy siliconcompound represented by the general formula (1b).
 14. The method as setforth in claim 11, wherein R_(1a) is a glycidoxy(C1-C3)alkyl group or analkyl group substituted with a cycloalkyl group of 5-8 carbons having anoxirane group in each of said at least one epoxy group-containing alkoxysilicon compound represented by the general formula (1a), and whereinR_(1b) is an alkyl group having at most 6 carbons or an aryl group ineach of said at least one substituted alkoxy silicon compoundrepresented by the general formula (1b).